Much progress has been made in the past ten years or so in the understanding of plasmons (collective electronic charge clouds), polaritons (composite photonic-electronic clouds- or quasi-particles) and the like, such as the plasmon-polariton (PP).
While various publications have alluded to the possibility that one day electronic circuits may be made using such physics to provide an optical computer, to date it appears that no concrete proposals have been published illustrating how such new physics might be brought together to create useful functional computing devices. Indeed, it is by no means obvious as to how this might be done.
Previous scientists and engineers have considered and attempted all-optical computing—and most have failed to deliver a competitive processor, for one reason or another. The main achievements to date have been succinctly reviewed by Miller [Miller, D. A. B., (2010) ‘Are optical transistors the logical next step?’, Nat. Photon., 4, 3.], which sets out the considerable challenges that need to be overcome in order to replace today's electronic computing with optical computing.
It should be noted that throughout this literature and in many more research papers, there is frequent mention of the dream of making an optical computer using plasmons at some point in the future, [Maier, S. A., et al., (2001) ‘Plasmonics—a route to nanoscale optical devices’, Advanced Materials, 13, 1501.]. Surface-plasmon (SPP) circuitry was proposed by analogy to optical fiber wave-guiding and coupling by [Ebbesen, T. W. et al., (May 2008) ‘Surface-plasmon circuitry’, Physics Today, 44.]—but not localized PP (LPP) circuitry as discussed in this application. Indeed, LPP circuitry requires a quite different geometry, and a different set of physics. It appears that no such comprehensive device architectures have yet been created that permit computing-element logic-functionality based on LPPs.